1. Field of the Invention
This application relates to motion capture. More particularly, this application relates to a motion capture system and method for tracking the motion of limbs.
2. Description of Related Art
Motion capture devices are available in a variety of formats and are used for, among other things, tracking the motion of one or more limbs of a wearer. Such devices may be used in a variety of manners, including video/entertainment, medical/rehabilitation, device or remote device actuation, etc. . . .
There are currently three main types of motion capture systems on the market. These are optical, inertial, and deformation-detecting type motion capture devices.
The first type of system is an optical motion capture device. These optical devices use one or more arrays of high-resolution cameras arranged around a stage on which action can take place. In most incarnations of such optical systems, the subjects are required to don suits studded in semi-reflective orbs about the size of table-tennis balls. The most prominent of these optical systems, and the current overall market leader, is that developed and sold by Vicon™.
A second type of motion capture system is the inertial system. These inertial system use inertial measurement units mounted to each limb segment and extremity of the subject. These units utilize a combination of accelerometric, magnetometric, and gyroscopic sensors that data from which is used to record the movement of the limbs, to which they are attached, in three-dimensional space. Such systems allow for limb tracking with a high degree of precision. Currently, the inertial system sold under the name Moven™ is probably the most recognized of these systems.
The third type of motion capture system uses deformation-detecting fiber optic strands embedded in flexible ribbons. The most notable example of this technique is probably the ShapeWrap II™ system by Measurand Systems™/Inition™.
Of the available motion capture systems, the Vicon™ optical type motion capture system is recognized to be the most accurate motion capture system, but is very limited in use. For example, such as system is limited to use within a limited area defined by the perimeter of cameras, and requires significant time to get subjects in and out of the suits they must wear. Such systems are also very expensive, both in the initial outlay for equipment, and in the expertise required for its use and maintenance.
The Moven™ inertial type motion capture system, owing to its intensive use of sensors, is both expensive, and also requires the use of a suit. Similarly, the ShapeWrap™ deformation-detecting motion capture technology from Measurand™ is also somewhat cumbersome and expensive.
In each case, the existing motion capture devices focus on professional and institutional markets, and the prices reflect this.